Bug Description

Currently it's not easy to migrate from the trusty vagrant box to the xenial box because of several differences :
- the vagrant user is not configured (#1569237)
- the virtual box extensions are not installed
- sudo doesn't resolve the hostname (#1561250)
- the disk space is 10GB instead of 40GB (#1580596)

I think that the process that was used to package the trusty box hasn't been used to package the xenial box. It seems the xenial box is a simple packaging of the raw image without any specific configuration for vagrant.